In U.S. applications Ser. No. 06/341,830 filed Jan. 22, 1982; Ser. No. 06/417,382 filed Sept. 13, 1982 (now U.S. Pat. No. 4,429,766); Ser. No. 06/492,487 filed May 6, 1983; and Ser. No. 06/537,276 filed Sept. 29, 1983 convertible ladders are disclosed and claimed. Each of these ladders are made up of U-shaped modules that are connected to each other by hinges that permit each module when not in use to fold or slide within its adjacent wider module. Each of these ladders has locking mechanisms that permit the modules to lock securely to each other when the ladder is in the extended or raised position.
In all the above-noted patent applications with the exception of Ser. No. 06/417,382, the U-shaped hinged modules are adpated to fold into their next wider modules when compacted for storage or to be transported. Since each hinged module will rotate 360.degree. on its hinged axis, many variations can be accomplished such as step ladders, workbenches, etc. In Ser. No. 06/537,276 a ladder conversion to a workbench is disclosed and illustrated in FIG. 6. This workbench is formed from the folding ladder merely by folding down the second (from bottom) and fifth (from bottom) modules. These modules are then locked in place and supported by brackets 32 in at least two corners. These brackets generally take the form of metal or plastic bars that have a projection on one end and an aperture on the opposite end. When this structure is to be used as a workbench it is highly desirable to have a working surface on which to work.